Gasoline fuel compositions having increased oxidative stability

ABSTRACT

The present invention relates to gasoline or a gasoline and ethanol blend fuel compositions that have improved oxidation stability. More specifically, the gasoline or a gasoline and ethanol blend fuel compositions include at least one antioxidant that increases the oxidative stability of the fuel. The gasoline or a gasoline and ethanol blend fuel compositions may also include an antioxidant mixture, or an antioxidant mixture in combination with a polar and/or nonpolar solvent, that increases the oxidative stability of the fuel.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Provisional Application Ser. No.60/778,537 filed on Mar. 2, 2006, which is hereby incorporated byreference in its entirety.

FIELD OF THE INVENTION

The present invention relates to gasoline or a gasoline and ethanolblend fuel compositions that have improved oxidation stability. Morespecifically, the gasoline and ethanol blend fuel compositions includeat least one antioxidant that increases the oxidative stability of thefuel.

BACKGROUND OF THE INVENTION

Gasoline and gasoline and ethanol blends compositions are typically usedas fuels for internal combustion engines. Various processes including acatalytic cracking process from crude oil and a catalytic reformingprocess from low-octane naphthas may be utilized to produce gasoline.Gasoline fuels, despite their method of production, easily oxidize inthe presence of oxygen, UV light, and heat. The products formed fromthis oxidation give rise to sediment or gum formation within the fueland may cause corrosion and plugging of internal combustion engines.

As such, there is a need for a gasoline or gasoline and ethanol blendcomposition having improved oxidation stability that reduces oreliminates sedimentation and gum formation within the fuel andconcomitantly, reduces or eliminates corrosion or plugging of internalcombustion engines.

SUMMARY OF THE INVENTION

One aspect of the present invention provides a fuel composition. Thefuel composition comprises gasoline; ethanol; and an antioxidantcomprising Formula (I):

wherein:

-   -   R¹, R², R³ and R⁴ are independently selected from the group        consisting of hydrogen and an alkyl group having from 1 to about        6 carbons;    -   R⁵ is an alkoxy group having from 1 to about 12 carbons.

Yet another aspect of the invention encompasses a fuel compositioncomprising gasoline in an amount ranging from about 60% to about 99% byweight of the composition; ethanol in an amount ranging from about 1% toabout 40% by weight of the composition; and6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline in an amount ranging fromabout 20 to about 1500 ppm.

A further aspect of the invention provides a method for increasing theoxidative stability of a fuel composition comprising gasoline andethanol. The method comprises contacting the fuel composition with anantioxidant comprising Formula (I):

wherein:

-   -   R¹, R², R³ and R⁴ are independently selected from the group        consisting of hydrogen and an alkyl group having from 1 to about        6 carbons;    -   R⁵ is an alkoxy group having from 1 to about 12 carbons.

Other aspects and iterations of the invention will be in part apparentand in part pointed out hereinafter.

FIGURES

FIG. 1 is a graph depicting the effect of ethanol on the inductionperiod of gasoline compositions. Plotted is the induction time versusthe amount of ethanol in each gasoline formulation.

FIG. 2 is a graph depicting effect of ethoxyquin (labeled as ETQ) on theinduction period of ethanol free gasoline.

FIG. 3 is a graph depicting the effect of ethoxyquin (ETQ) and ethanol(ETOH) on the induction period. Plotted is the induction period inminutes versus level of ethoxyquin in ppm.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides gasoline fuel compositions that haveimproved oxidative stability. Typically, the gasoline fuel compositionscomprise gasoline, at least one antioxidant that increases gasolinestability, and optionally, ethanol. In addition to improved oxidativestability, the gasoline fuel compositions also may have longer inductiontimes, lower amounts of insolubes, and lower peroxide values.Advantageously, the gasoline fuel compositions may also have lowerNO_(x) and CO₂ emissions.

I. Gasoline

The fuel composition of the invention includes gasoline. Gasolinesuitable for use in the invention is typically a petroleum-derivedliquid mixture consisting mostly of hydrocarbons used as fuel ininternal combustion engines. The hydrocarbons forming the gasolinegenerally consist of between 5 to about 12 carbon atoms per molecule. Atypical gasoline may include a mixture of paraffins, naphthenes,aromatics, and olefins. The ratios of these components forming gasolinesuitable for use in the invention can and will vary depending on avariety of factors, such as, the oil refining process, the crude oilused, and the grade of gasoline.

Exemplary gasoline formulations will generally have a relatively highoctane rating. The gasoline composition, for example, may have an octanerating of greater than about 85%, about 86%, about 87%, about 88%, about89%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%,about 96%, about 97%, about 98%, about 99%, or about 100%. Octane ratingmay be measured by any method generally known in the art, such as by theResearch Octane Number (i.e., RON). Generally speaking, in this methodoctane rating of gasoline is typically measured relative to a mixture ofisooctane (i.e., 2,2,4-trimethylpentane) and n-heptane by running thefuel samples through a specific test engine with a variable compressionratio under controlled conditions. By way of example, an 87-octanegasoline typically has the same octane rating as a mixture of 87% (v/v)isooctane and 13% (v/v) n-heptane.

A variety of methods known in the art may be used to make the gasolineof the present invention. The gasoline may be produced through acatalytic cracking process from crude oil. As used herein, a catalyticcracking process is defined as a refining process by which certain crudecuts are broken down or “cracked” into simpler hydrocarbon compounds atthe molecular level by means of extreme heat, pressure, and exposure toa chemical catalyst. Alternatively, gasoline may be produced by acatalytic reforming process. A variety of catalytic reforming processesare suitable to produce gasoline, including but not limited to,platforming, powerforming, ultraforming, and Thermofor catalyticreforming. Generally, in a catalytic reforming process low-octanenaphthas are subjected to a high temperatures and relatively mildhydrogen partial pressures in the presence of multinuclear catalysts,such as platinum, or rhenium, or on a carrier such as zeolites. Duringthe process, the naphtha feedstock, mainly consisting of paraffins,undergoes numerous reactions including hydrogenation, alkylation,polymerization, cracking, cyclization, isomerization, among others. Theprocess produces light paraffinic gases (LPG), hydrogen, and thearomatic and naphthenic compounds that make up the backbone ofhigh-octane gasoline, such as benzene, toluene, cyclopentane,cyclohexane, and ethyl-benzene, among others. Alternatively, thegasoline may be purchased from a commercially available source.

II. Ethanol

The present invention also contemplates fuels that are blends ofgasoline and ethanol. Generally speaking, ethanol, also known as ethylalcohol or grain alcohol, is used as fuel or as an octane-boosting,pollution-reducing additive to gasoline.

The ethanol may be present in a gasoline ethanol mixture in an amountranging from about 0% to about 5%, from about 5% to about 10%, fromabout 10% to about 15%, from about 15% to about 20%, from about 20% toabout 25%, from about 25% to about 30%, from about 30% to about 35%,from about 35% to about 40%, from about 40% to about 45%, from about 45%to about 50%, from about 50% to about 55%, from about 55% to about 60%,from about 60% to about 65%, from about 65% to about 70%, from about 70%to about 75%, from about 75% to about 80%, from about 80% to about 85%,from about 85% to about 90%, from about 90% to about 95%, or greaterthan about 95% by weight of the composition. Exemplary compositions mayinclude ethanol in an amount ranging from about 5% to about 10%, fromabout 10% to about 15%, from about 15% to about 20%, from about 20% toabout 25%, from about 25% to about 30%, from about 30% to about 35%, orless than 40% by weight of the composition.

Ethanol may be produced using a variety of feedstocks. For example,ethanol may be produced from biomass or crops. In one embodiment, theethanol is produced from a crop. Suitable crops for ethanol productioninclude corn, milo, sorghum, wheat, barley, potatoes, sugarcane, hemp,kenaf, sugar beets, barley, cassaya, sunflower, seaweed, and eucalyptus.It is, however, envisioned that other crops may also be used withoutdeparting from the scope of the invention. In another embodiment, theethanol is produced from biomass. Suitable biomass for ethanolproduction may include farm wastes, agricultural forestry residues,industrial waste, municipal waste, trees, grasses, sugarcane residues,rice hulls, paper mill wastes, molasses, and other organic or cellulosematerials. In yet another embodiment, the ethanol is produced from aplant-derived, cellulose material. Suitable plant-derived, cellulosematerials include switchgrass, corncobs, wheat straw, corn stover, andsawdust. As will be appreciated by the skilled artisan, ethanol may alsobe produced from a combination of different sources. In an exemplaryembodiment, the ethanol is produced from a source selected from thegroup consisting of corn, grain sorghum, wheat, barley, potatoes, sugarcane, plant-derived cellulose material, and biomass. In a furtherexemplary embodiment, the ethanol is produced from corn. In anotherexemplary embodiment, the ethanol is produced from a plant-derivedcellulose material.

Several methods generally known in the art may be used to produceethanol without departing from the scope of the invention. In general,ethanol may be produced by chemical synthesis or biologicalfermentation. Chemical synthesis involves the hydrolysis of ethyleneobtained from coal gasification or other mineral livestock. This methodis generally used for low volume applications that need unusually highpurity, anhydrous ethanol and fills a niche market found in the chemicalindustry. Fermentation for the production of ethanol utilizesmicroorganisms, most commonly yeast, for the conversion of sugars toalcohols. This process occurs in the absence of oxygen forcing themicroorganisms to utilize an anaerobic metabolic pathway. This pathwayconverts sugars into ethanol, carbon dioxide, chemical energy, andkinetic (heat) energy. Typically, a dry mill process produces fuel gradeethanol from grains. Such a process typically includes milling,liquefaction, saccharification, fermentation, distillation, dehydration,and denaturing. Another embodiment that may be used to produce ethanolincludes contacting a biomass with genetically engineered EscherichiaColi strains, as disclosed in U.S. Pat. No. 5,000,000, hereinincorporated by reference. Alternatively, the ethanol may be purchasedfrom a commercially available source.

II. Antioxidants

The gasoline composition of the invention also includes one or moreantioxidants. Suitable antioxidants for use in the present inventionsubstantially inhibit the oxidation process and thus, enhance the fuelcomposition's oxidative stability. Methods for measuring oxidativestability of a gasoline composition are described in more detail below,and in particular, in the Examples.

(a) Individual Antioxidants

Those skilled in the art will appreciate that several suitableantioxidants may be used depending on the type of fuel to be stabilized.In one embodiment, the antioxidant may be selected from the groupcomprising of hindered amines, such as diphenyl amines; butylatedhydroxyanisole; butylated hydroxytoluene; gallates such as octylgallate, dodecyl gallate, and 3,4,5-trihydroxybenzoic acid n-propylester (propyl gallate); 1,2,3-trihydroxybenzene (pyrogallol); fatty acidesters including, but not limited to, methyl esters such as methyllinoleate, methyl oleate, methyl stearate,2,2,6,6-tetramethylpiperidinooxy, also referred to as tanan;2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl, also referred to astanol; dimethyl-p-phenylaminophenoxysilane; di-p-anisylazoxides;p-hydroxydiphenylamine, and carbonates, phthalates, and adipatesthereof; and diludin, a 1,4-dihydropyridine derivative.

In another embodiment, the antioxidant may be selected from the groupcomprising oil-soluble antioxidants, including, but not limited toascorbyl palmitate, butylated hydroxyanisole, butylated hydroxytoluene,phenyl-alpha-naphthylamine, and hydroquinone.

In a further embodiment, the antioxidant may be a synthetic antioxidantsselected from the phenolic acids and derivatives;2-tert-butylhydroquinone (TBHQ); mixtures of TBHQ and2-tertiarybutyl-4-hydroxyanisole; 3-tertiarybutyl-4-hydroxyanisole;2,6-di-tert-butyl-4-hydroxymethylphenol;2-6-di-tert-butyl-4-methylphenol (BHT) and t-tert-butyl-4-methylphenol(t-BHT); 2-ter-butyl-4-methoxyphenol (BHA); mono tertiary butylhydroquinone, di-tert-butyl hydroquinone, polyphosphates; trihydroxybutyrophenone; anoxomer; and combinations thereof. Other suitablesynthetic antioxidants include the antioxidants marketed under the namesVANLUBE, IONOL, and BAYNOX.

In another embodiment, the antioxidant may be a quinoline or asubstituted quinoline. In an exemplary embodiment, the quinoline is asubstituted 1,2-dihydroquinoline compound. Substituted1,2-dihydroquinoline compounds suitable for use in the invention maycorrespond to formula (I):

wherein:

-   -   R¹, R², R³ and R⁴ are independently selected from the group        consisting of hydrogen and an alkyl group having from 1 to about        6 carbons;    -   R⁵ is an alkoxy group having from 1 to about 12 carbons.

In another embodiment, the substituted 1,2-dihydroquinoline will haveformula (I) wherein:

-   -   R¹, R², R³ and R⁴ are independently selected from the group        consisting of hydrogen and an alkyl group having from 1 to about        4 carbons; and    -   R⁵ is an alkoxy group having from 1 to about 4 carbons.

An exemplary substituted 1,2-dihydroquinoline is6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline having the formula:

6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, commonly known asethoxyquin, is sold under the trademark SANTOQUIN® (by NovusInternational Inc. of Saint Louis Mo.). The present invention alsoencompasses salts of ethoxyquin and other compounds having formula (I).Ethoxyquin and other compounds having formula (I) may be purchasedcommercially from Novus International, Inc. or made in accordance withmethods generally known in the art, for example, as detailed in U.S.Pat. No. 4,772,710, which is hereby incorporated by reference in itsentirety.(b) Antioxidant Formulations

The antioxidant may be a blend of any of the antioxidants detailed inII(a). For example, the antioxidant may include, two, three, four, fiveor more of any of the aforementioned antioxidants. In an exemplaryembodiment, the antioxidant blend will include a compound having formula(I). Non-limiting examples of suitable antioxidant blends are detailedin Table A. TABLE A First Antioxidant Second Antioxidant or AntioxidantMixture 6-ethoxy-1,2-dihydro-2,2,4- 2-tert-butylhydroquinonetrimethylquinoline 6-ethoxy-1,2-dihydro-2,2,4- 3,4,5-trihydroxybenzoicacid n-propyl ester trimethylquinoline 6-ethoxy-1,2-dihydro-2,2,4-1,2,3-trihydroxybenzene trimethylquinoline 6-ethoxy-1,2-dihydro-2,2,4-2-tert-butyl-4-hydroxyanisole trimethylquinoline6-ethoxy-1,2-dihydro-2,2,4- t-tert-butyl-4-methylphenoltrimethylquinoline 6-ethoxy-1,2-dihydro-2,2,4-2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene trimethylquinoline6-ethoxy-1,2-dihydro-2,2,4- dodecyl gallate trimethylquinoline6-ethoxy-1,2-dihydro-2,2,4- octyl gallate trimethylquinoline6-ethoxy-1,2-dihydro-2,2,4- 2-tert-butylhydroquinone and 3,4,5-trimethylquinoline trihydroxybenzoic acid n-propyl ester6-ethoxy-1,2-dihydro-2,2,4- 2-tert-butylhydroquinone and 1,2,3-trimethylquinoline trihydroxybenzene 6-ethoxy-1,2-dihydro-2,2,4-1,2,3-trihydroxybenzene and 2-tert-butyl-4- trimethylquinolinehydroxyanisole 6-ethoxy-1,2-dihydro-2,2,4- 1,2,3-trihydroxybenzene andt-tert-butyl-4- trimethylquinoline methylphenol6-ethoxy-1,2-dihydro-2,2,4- 1,2,3-trihydroxybenzene and2,6-Di-tert-Butyl-1- trimethylquinoline Hydroxy-4-Methylbenzene6-ethoxy-1,2-dihydro-2,2,4- 1,2,3-trihydroxybenzene and dodecyl gallatetrimethylquinoline 6-ethoxy-1,2-dihydro-2,2,4- 1,2,3-trihydroxybenzeneand octyl gallate trimethylquinoline 6-ethoxy-1,2-dihydro-2,2,4-3,4,5-trihydroxybenzoic acid n-propyl ester and trimethylquinoline1,2,3-trihydroxybenzene 6-ethoxy-1,2-dihydro-2,2,4-3,4,5-trihydroxybenzoic acid n-propyl ester and trimethylquinoline2-tert-butyl-4-hydroxyanisole 6-ethoxy-1,2-dihydro-2,2,4-3,4,5-trihydroxybenzoic acid n-propyl ester and trimethylquinolinet-tert-butyl-4-methylphenol 6-ethoxy-1,2-dihydro-2,2,4-3,4,5-trihydroxybenzoic acid n-propyl ester and trimethylquinoline2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene 6-ethoxy-1,2-dihydro-2,2,4-3,4,5-trihydroxybenzoic acid n-propyl ester and trimethylquinolinedodecyl gallate 6-ethoxy-1,2-dihydro-2,2,4- 3,4,5-trihydroxybenzoic acidn-propyl ester and trimethylquinoline octyl gallate6-ethoxy-1,2-dihydro-2,2,4- 1,2,3-trihydroxybenzene and 2-tert-butyl-4-trimethylquinoline hydroxyanisole 6-ethoxy-1,2-dihydro-2,2,4-1,2,3-trihydroxybenzene and t-tert-butyl-4- trimethylquinolinemethylphenol 6-ethoxy-1,2-dihydro-2,2,4- 1,2,3-trihydroxybenzene and2,6-Di-tert-Butyl-1-Hydroxy- trimethylquinoline 4-Methylbenzene6-ethoxy-1,2-dihydro-2,2,4- 1,2,3-trihydroxybenzene and dodecyl gallatetrimethylquinoline 6-ethoxy-1,2-dihydro-2,2,4- 1,2,3-trihydroxybenzeneand octyl gallate trimethylquinoline 6-ethoxy-1,2-dihydro-2,2,4-2-tert-butyl-4-hydroxyanisole and 2,6-Di-tert- trimethylquinolineButyl-1-Hydroxy-4-Methylbenzene 6-ethoxy-1,2-dihydro-2,2,4-2-tert-butyl-4-hydroxyanisole and dodecyl trimethylquinoline gallate6-ethoxy-1,2-dihydro-2,2,4- 2-tert-butyl-4-hydroxyanisole andt-tert-butyl-4- trimethylquinoline methylphenol6-ethoxy-1,2-dihydro-2,2,4- 2-tert-butyl-4-hydroxyanisole and octylgallate trimethylquinoline 6-ethoxy-1,2-dihydro-2,2,4-t-tert-butyl-4-methylphenol and 2,6-Di-tert-Butyl- trimethylquinoline1-Hydroxy-4-Methylbenzene 6-ethoxy-1,2-dihydro-2,2,4-t-tert-butyl-4-methylphenol and dodecyl gallate trimethylquinoline6-ethoxy-1,2-dihydro-2,2,4- t-tert-butyl-4-methylphenol and octylgallate trimethylquinoline 6-ethoxy-1,2-dihydro-2,2,4-2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene trimethylquinoline anddodecyl gallate 6-ethoxy-1,2-dihydro-2,2,4-2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene trimethylquinoline and octylgallate 6-ethoxy-1,2-dihydro-2,2,4- dodecyl gallate and octyl gallatetrimethylquinoline 6-ethoxy-1,2-dihydro-2,2,4-2-tert-butyl-4-hydroxyanisole and 2,6-Di-tert-Butyl- trimethylquinoline1-Hydroxy-4-Methylbenzene 6-ethoxy-1,2-dihydro-2,2,4-2-tert-butyl-4-hydroxyanisole and 2,6-Di-tert- trimethylquinolineButyl-1-Hydroxy-4-Methylbenzene and 2-tert- butylhydroquinone6-ethoxy-1,2-dihydro-2,2,4- 2-tert-butylhydroquinone and paraffin oiltrimethylquinoline 6-ethoxy-1,2-dihydro-2,2,4-2-tert-butyl-4-hydroxyanisole and 2,6-Di-tert- trimethylquinolineButyl-1-Hydroxy-4-Methylbenzene and paraffin oil6-ethoxy-1,2-dihydro-2,2,4- 2-tert-butylhydroquinone, 1,2-Propanediol,and paraffin trimethylquinoline oil(c) Solvents

The antioxidant composition may further comprise a polar solvent or anon-polar solvent. Generally speaking, a polar solvent may be utilizedto solubilize any of the antioxidants that are water-soluble and thenon-polar solvent may be utilized to solubilize hydrophobicantioxidants. Suitable examples of polar solvents include, but are notlimited to, alcohols such as methanol, glycerol, isopropyl alcohol,ethyl alcohol, propylene glycol, erythritol, xylitol, sorbitol,maltitol, mannitol, water, or combinations thereof. In one embodiment,the polar solvent is glycerol. In another embodiment, the polar solventis propylene glycol. Other suitable solvents include hexane, xylene,octane, and paraffins. The concentration of the solvent will varydepending upon the combination of antioxidants in the composition. Ingeneral, the percent by volume of the solvent may range from about 5% toabout 50%. The percent by volume of glycerol may be about 5%, 10%, 15%,20%, or 25%. The percent by volume of propylene glycol may be about 5%,10%, 15%, 20%, or 25%.

III. Fuel Compositions

The invention provides several suitable combinations of gasoline,ethanol, and antioxidants. In one alternative, the fuel composition maycomprise gasoline and one antioxidant. In another alternative, the fuelcomposition may comprise gasoline, ethanol, and one antioxidant. In yeta further alternative, the fuel composition may comprise gasoline and atleast two antioxidants. In this embodiment, the fuel composition may begasoline in combination with any of the antioxidants described in PartII other than 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline. Suitablecombinations of each type of fuel composition are detailed below.

(a) Fuel Composition with Gasoline and One Antioxidant

Examples of exemplary fuel compositions having gasoline and oneantioxidant are presented in Table 1 below. Alternatively, each fuelcomposition detailed in Table 1 may also include6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline. TABLE 1 Fuel AntioxidantsGasoline 2-tert-butylhydroquinone Gasoline 3,4,5-trihydroxybenzoic acidn-propyl ester Gasoline 1,2,3-trihydroxybenzene Gasoline2-tert-butyl-4-hydroxyanisole Gasoline t-tert-butyl-4-methylphenolGasoline 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene Gasoline dodecylgallate Gasoline octyl gallate(b) Fuel Composition with Gasoline, Ethanol and One Antioxidant

In another embodiment, the fuel composition of the invention comprises ablend of gasoline, ethanol, and one antioxidant that increases theoxidative stability of the fuel composition. In this embodiment, thefuel composition may be any of the ethanols described in Part I incombination with a gasoline and any of the antioxidants described inPart II. Generally speaking, the fuel composition may comprise fromabout 15% to about 95% by weight gasoline and from about 5% to about 85%by weight ethanol. In another embodiment, the fuel composition maycomprise from about 80% to about 95% by weight gasoline and from about5% to about 20% by weight ethanol. In an alternative embodiment, thefuel composition may comprise from about 90% to about 95% by weightgasoline and from about 5% to about 10% by weight ethanol. Examples ofexemplary fuel compositions are presented in Table 2 below.Alternatively, each fuel composition detailed in Table 2 may alsoinclude 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline. TABLE 2 EthanolFuel Fuel Raw Material Antioxidants Gasoline Corn2-tert-butylhydroquinone Gasoline Corn 3,4,5-trihydroxybenzoic acidn-propyl ester Gasoline Corn 1,2,3-trihydroxybenzene Gasoline Corn2-tert-butyl-4-hydroxyanisole Gasoline Corn t-tert-butyl-4-methylphenolGasoline Corn 2,6-Di-tert-Butyl-1-Hydroxy-4- Methylbenzene Gasoline Corndodecyl gallate Gasoline Corn octyl gallate Gasoline Plant-derived2-tert-butylhydroquinone cellulose material Gasoline Plant-derived3,4,5-trihydroxybenzoic acid n-propyl ester cellulose material GasolinePlant-derived 1,2,3-trihydroxybenzene cellulose material GasolinePlant-derived 2-tert-butyl-4-hydroxyanisole cellulose material GasolinePlant-derived t-tert-butyl-4-methylphenol cellulose material GasolinePlant-derived 2,6-Di-tert-Butyl-1-Hydroxy-4- cellulose Methylbenzenematerial Gasoline Plant-derived dodecyl gallate cellulose materialGasoline Plant-derived octyl gallate cellulose material GasolineSugarcane 2-tert-butylhydroquinone Gasoline Sugarcane3,4,5-trihydroxybenzoic acid n-propyl ester Gasoline Sugarcane1,2,3-trihydroxybenzene Gasoline Sugarcane 2-tert-butyl-4-hydroxyanisoleGasoline Sugarcane t-tert-butyl-4-methylphenol Gasoline Sugarcane2,6-Di-tert-Butyl-1-Hydroxy-4- Methylbenzene Gasoline Sugarcane dodecylgallate Gasoline Sugarcane octyl gallate Gasoline Grain sorghum2-tert-butylhydroquinone Gasoline Grain sorghum 3,4,5-trihydroxybenzoicacid n-propyl ester Gasoline Grain sorghum 1,2,3-trihydroxybenzeneGasoline Grain sorghum 2-tert-butyl-4-hydroxyanisole Gasoline Grainsorghum t-tert-butyl-4-methylphenol Gasoline Grain sorghum2,6-Di-tert-Butyl-1-Hydroxy-4- Methylbenzene Gasoline Grain sorghumdodecyl gallate Gasoline Grain sorghum octyl gallate Gasoline Wheat2-tert-butylhydroquinone Gasoline Wheat 3,4,5-trihydroxybenzoic acidn-propyl ester Gasoline Wheat 1,2,3-trihydroxybenzene Gasoline Wheat2-tert-butyl-4-hydroxyanisole Gasoline Wheat t-tert-butyl-4-methylphenolGasoline Wheat 2,6-Di-tert-Butyl-1-Hydroxy-4- Methylbenzene GasolineWheat dodecyl gallate Gasoline Wheat octyl gallate Gasoline Barley2-tert-butylhydroquinone Gasoline Barley 3,4,5-trihydroxybenzoic acidn-propyl ester Gasoline Barley 1,2,3-trihydroxybenzene Gasoline Barley2-tert-butyl-4-hydroxyanisole Gasoline Barleyt-tert-butyl-4-methylphenol Gasoline Barley2,6-Di-tert-Butyl-1-Hydroxy-4- Methylbenzene Gasoline Barley dodecylgallate Gasoline Barley octyl gallate Gasoline Potatoes2-tert-butylhydroquinone Gasoline Potatoes 3,4,5-trihydroxybenzoic acidn-propyl ester Gasoline Potatoes 1,2,3-trihydroxybenzene GasolinePotatoes 2-tert-butyl-4-hydroxyanisole Gasoline Potatoest-tert-butyl-4-methylphenol Gasoline Potatoes2,6-Di-tert-Butyl-1-Hydroxy-4- Methylbenzene Gasoline Potatoes dodecylgallate Gasoline Potatoes octyl gallate Gasoline Biomass2-tert-butylhydroquinone Gasoline Biomass 3,4,5-trihydroxybenzoic acidn-propyl ester Gasoline Biomass 1,2,3-trihydroxybenzene Gasoline Biomass2-tert-butyl-4-hydroxyanisole Gasoline Biomasst-tert-butyl-4-methylphenol Gasoline Biomass2,6-Di-tert-Butyl-1-Hydroxy-4- Methylbenzene Gasoline Biomass dodecylgallate Gasoline Biomass octyl gallate

In one preferred embodiment, the fuel composition comprises a gasoline,an ethanol produced from corn, and6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline. In another preferredembodiment, the fuel composition comprises a gasoline, an ethanolproduced from sugarcane, and6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline. In yet another preferredembodiment, the fuel composition comprises a gasoline, an ethanolproduced from a plant-derived, cellulose material and6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline. In another preferredembodiment, the fuel composition comprises a gasoline, an ethanolproduced from a biomass, and6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline. Those skilled in the artwill appreciate that the concentration of antioxidants added to thegasoline and ethanol blend can and will vary depending on the source ofethanol. In one embodiment, the fuel composition comprises a gasoline,an ethanol produced from a plant-derived, cellulose material, and fromabout 20 ppm to about 1500 ppm of6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline. In another embodiment,the fuel composition comprises a gasoline, an ethanol produced fromcorn, and from about 50 ppm to about 500 ppm of6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline.

(c) Fuel Composition with Gasoline and at least two Antioxidants

The present invention is also directed to a fuel composition comprisinga gasoline and an antioxidant mixture comprising at least twoantioxidants. In one embodiment, the fuel composition comprises thegasoline as described in Part I and an antioxidant mixture comprising atleast two antioxidants as described in Part II of the specificationabove. Of course those skilled in the art will appreciate that theantioxidant mixtures will vary considerably depending on the desiredstabilization of the gasoline. Examples of exemplary fuel compositionsare presented in Table 3 below. TABLE 3 Fuel Antioxidants Gasoline2-tert-butylhydroquinone and 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline Gasoline 2-tert-butyl-4-hydroxyanisole and2,6-Di-tert-Butyl-1- Hydroxy-4-Methylbenzene Gasoline2-tert-butyl-4-hydroxyanisole and 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene and 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline Gasoline 2-tert-butyl-4-hydroxyanisole and2,6-Di-tert-Butyl-1- Hydroxy-4-Methylbenzene and 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline and 2-tert-butylhydroquinone Gasoline2-tert-butylhydroquinone and 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline and paraffin oil Gasoline2-tert-butyl-4-hydroxyanisole and 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene and paraffin oil Gasoline6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline and 2-tert-butylhydroquinone, 1,2-Propanediol, and paraffin oil

In one embodiment, the fuel composition comprises a gasoline and anantioxidant mixture comprising 2-tert-butylhydroquinone (TBHQ) and6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline (EQ). Such an antioxidantmixture is sold under the trademark SANTOQUIN Q® and may be purchasedcommercially from Novus International, Inc. In another embodiment, thefuel composition comprises a gasoline and an antioxidant mixturecomprising 2-tert-butyl-4-hydroxyanisole (BHA) and2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene (BHT). In yet anotherembodiment, the fuel composition comprises a gasoline and an antioxidantmixture comprising 2-tert-butyl-4-hydroxyanisole,2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene and6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline. In a further embodiment,the fuel composition comprises a gasoline and an antioxidant mixturecomprising 2-tert-butylhydroquinone,6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline,2-tert-butyl-4-hydroxyanisole, and2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene.

In another embodiment, the fuel composition comprises a gasoline and anantioxidant mixture comprising 2-tert-butylhydroquinone,6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, and a paraffin oil. Inyet another embodiment, the fuel composition comprises a gasoline and anantioxidant mixture comprising 2-tert-butyl-4-hydroxyanisole,2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene, and a paraffin oil. In afurther embodiment, the fuel composition comprises a gasoline and anantioxidant mixture comprising6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, 2-tert-butylhydroquinone,1,2-Propanediol, and a paraffin oil.

Those skilled in the art will appreciate that the concentration ofantioxidants added to the gasoline can and will vary depending on thedesired stability of the fuel. In one embodiment, the fuel compositioncomprises a gasoline and an antioxidant mixture comprising from about 20ppm to about 500 ppm of 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline,from about 20 ppm to about 500 ppm of a mixture of2-tert-butyl-4-hydroxyanisole and2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene, and from about 10 to about60 ppm of 2-tert-butylhydroquinone. In another embodiment, the fuelcomposition comprises a gasoline and an antioxidant mixture comprisingabout 400 ppm of 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, about 40ppm of a mixture of 2-tert-butyl-4-hydroxyanisole and2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene, and about 50 ppm of2-tert-butylhydroquinone. In yet another embodiment, the fuelcomposition comprises a gasoline and an antioxidant mixture comprisingabout 40 ppm of 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, about 40ppm of a mixture of 2-tert-butyl-4-hydroxyanisole and2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene, and about 50 ppm of2-tert-butylhydroquinone.

(d) Fuel Composition with Gasoline, Ethanol and at Least TwoAntioxidants

In another embodiment, the fuel composition of the invention comprises agasoline and an ethanol blend in combination with an antioxidant mixturecomprising at least two antioxidants wherein the fuel composition hassubstantially improved oxidative stability. The fuel composition maycomprise from about 15% to about 95% by weight gasoline and from about5% to about 85% by weight ethanol. In another embodiment, the fuelcomposition may comprise from about 80% to about 95% by weight gasolineand from about 5% to about 20% by weight ethanol. In an alternativeembodiment, the fuel composition may comprise from about 90% to about95% by weight gasoline and from about 5% to about 10% by weight ethanol.In one embodiment, the fuel composition comprises any of the ethanolsdescribed in Part I in combination with a gasoline and an antioxidantmixture comprising at least two antioxidants as described in Part II ofthe specification above. Exemplary fuel compositions are presented inTable 4 below. TABLE 4 Ethanol Fuel Raw Fuel Material AntioxidantsGasoline Corn 2-tert-butylhydroquinone and 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline Gasoline Corn2-tert-butyl-4-hydroxyanisole and 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene Gasoline Corn2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene and 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline Gasoline Corn2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene, 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline and 2-tert-butylhydroquinoneGasoline Corn 2-tert-butylhydroquinone, 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline and paraffin oil Gasoline Corn2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene and paraffin oil Gasoline Corn6-ethoxy-1,2-dihydro-2,2,4- trimethylquinoline, 2-tert-butylhydroquinone, 1,2-Propanediol, and paraffin oil GasolinePlant-derived 2-tert-butylhydroquinone and 6-ethoxy-1,2- Cellulosedihydro-2,2,4-trimethylquinoline Material Gasoline Plant-derived2-tert-butyl-4-hydroxyanisole and 2,6-Di- Cellulosetert-Butyl-1-Hydroxy-4-Methylbenzene Material Gasoline Plant-derived2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert- CelluloseButyl-1-Hydroxy-4-Methylbenzene and 6- Materialethoxy-1,2-dihydro-2,2,4-trimethylquinoline Gasoline Plant-derived2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert- CelluloseButyl-1-Hydroxy-4-Methylbenzene, 6- Materialethoxy-1,2-dihydro-2,2,4-trimethylquinoline and 2-tert-butylhydroquinoneGasoline Plant-derived 2-tert-butylhydroquinone, 6-ethoxy-1,2- Cellulosedihydro-2,2,4-trimethylquinoline and Material paraffin oil GasolinePlant-derived 2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert- CelluloseButyl-1-Hydroxy-4-Methylbenzene and Material paraffin oil GasolinePlant-derived 6-ethoxy-1,2-dihydro-2,2,4- Cellulose trimethylquinoline,2-tert- Material butylhydroquinone, 1,2-Propanediol, and paraffin oilGasoline Sugarcane 2-tert-butylhydroquinone and 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline Gasoline Sugarcane2-tert-butyl-4-hydroxyanisole and 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene Gasoline Sugarcane2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene and 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline Gasoline Sugarcane2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene, 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline and 2-tert-butylhydroquinoneGasoline Sugarcane 2-tert-butylhydroquinone, 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline and paraffin oil Gasoline Sugarcane2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene and paraffin oil Gasoline Sugarcane6-ethoxy-1,2-dihydro-2,2,4- trimethylquinoline, 2-tert-butylhydroquinone, 1,2-Propanediol, and paraffin oil Gasoline Grainsorghum 2-tert-butylhydroquinone and 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline Gasoline Grain sorghum2-tert-butyl-4-hydroxyanisole and 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene Gasoline Grain sorghum2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene and 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline Gasoline Grain sorghum2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene, 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline and 2-tert-butylhydroquinoneGasoline Grain sorghum 2-tert-butylhydroquinone, 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline and paraffin oil Gasoline Grain sorghum2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene and paraffin oil Gasoline Grain sorghum6-ethoxy-1,2-dihydro-2,2,4- trimethylquinoline, 2-tert-butylhydroquinone, 1,2-Propanediol, and paraffin oil Gasoline Wheat2-tert-butylhydroquinone and 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline Gasoline Wheat2-tert-butyl-4-hydroxyanisole and 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene Gasoline Wheat2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene and 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline Gasoline Wheat2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene, 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline and 2-tert-butylhydroquinoneGasoline Wheat 2-tert-butylhydroquinone, 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline and paraffin oil Gasoline Wheat2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene and paraffin oil Gasoline Wheat6-ethoxy-1,2-dihydro-2,2,4- trimethylquinoline, 2-tert-butylhydroquinone, 1,2-Propanediol, and paraffin oil Gasoline Barley2-tert-butylhydroquinone and 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline Gasoline Barley2-tert-butyl-4-hydroxyanisole and 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene Gasoline Barley2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene and 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline Gasoline Barley2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene, 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline and 2-tert-butylhydroquinoneGasoline Barley 2-tert-butylhydroquinone, 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline and paraffin oil Gasoline Barley2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene and paraffin oil Gasoline Barley6-ethoxy-1,2-dihydro-2,2,4- trimethylquinoline, 2-tert-butylhydroquinone, 1,2-Propanediol, and paraffin oil Gasoline Potatoes2-tert-butylhydroquinone and 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline Gasoline Potatoes2-tert-butyl-4-hydroxyanisole and 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene Gasoline Potatoes2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene and 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline Gasoline Potatoes2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene, 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline and 2-tert-butylhydroquinoneGasoline Potatoes 2-tert-butylhydroquinone, 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline and paraffin oil Gasoline Potatoes2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene and paraffin oil Gasoline Potatoes6-ethoxy-1,2-dihydro-2,2,4- trimethylquinoline, 2-tert-butylhydroquinone, 1,2-Propanediol, and paraffin oil Gasoline Biomass2-tert-butylhydroquinone and 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline Gasoline Biomass2-tert-butyl-4-hydroxyanisole and 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene Gasoline Biomass2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene, and 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline Gasoline Biomass2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene, 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline and 2-tert-butylhydroquinoneGasoline Biomass 2-tert-butylhydroquinone, 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline and paraffin oil Gasoline Biomass2-tert-butyl-4-hydroxyanisole, 2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene and paraffin oil Gasoline Biomass6-ethoxy-1,2-dihydro-2,2,4- trimethylquinoline and 2-tert-butylhydroquinone, 1,2-Propanediol, and paraffin oil

In one embodiment, the fuel composition comprises a gasoline, an ethanolproduced from a plant-derived cellulose material, and an antioxidantmixture comprising 2-tert-butylhydroquinone (TBHQ) and6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline (EQ). In anotherembodiment, the fuel composition comprises a gasoline, an ethanolproduced from a plant-derived cellulose material, and an antioxidantmixture comprising 2-tert-butyl-4-hydroxyanisole (BHA) and2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene (BHT). In yet anotherembodiment, the fuel composition comprises a gasoline, an ethanolproduced from a plant-derived cellulose material, and an antioxidantmixture comprising 2-tert-butyl-4-hydroxyanisole,2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene and6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline. In a further embodiment,the fuel composition comprises a gasoline, an ethanol produced from aplant-derived cellulose material, and an antioxidant mixture comprising2-tert-butylhydroquinone, 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline,2-tert-butyl-4-hydroxyanisole, and2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene.

In another embodiment, the fuel composition comprises a gasoline, anethanol produced from a plant-derived cellulose material, and anantioxidant mixture comprising 2-tert-butylhydroquinone,6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, and a paraffin oil. Inyet another embodiment, the fuel composition comprises a gasoline, anethanol produced from a plant-derived cellulose material, and anantioxidant mixture comprising 2-tert-butyl-4-hydroxyanisole,2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene, and a paraffin oil. In afurther embodiment, the fuel composition comprises a gasoline, anethanol produced from a plant-derived cellulose material, and anantioxidant mixture comprising6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, 2-tert-butylhydroquinone,1,2-Propanediol, and a paraffin oil.

Gumming

Those skilled in the art will appreciate that the concentration ofantioxidants added to the gasoline and ethanol blend will generally bethe amount needed to achieve an induction period of greater than about1400 minutes. In one embodiment, the fuel composition comprises agasoline and ethanol blend, and an antioxidant mixture comprising fromabout 20 ppm to about 500 ppm of6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, from about 20 ppm toabout 500 ppm of a mixture of 2-tert-butyl-4-hydroxyanisole and2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene, and from about 10 to about60 ppm of 2-tert-butylhydroquinone.

IV. Additional Agents

The fuel compositions of the invention may contain additional agentsthat enhance one or more characteristics of the fuel. Those skilled inthe art will appreciate that the selection of the particular agent mayvary considerably depending on the type of fuel used. Suitableadditives, for example, may include, but are not limited to, one or moreoctane improvers, demulsifiers, corrosion inhibitors and/or metaldeactivators, cold flow improvers, and the like, as described below.

Thermal stabilizers may optionally be added to the gasoline composition.Suitable thermal stabilizers known in the art include liquid mixtures ofalkyl phenols, including 2-tert-butylphenol, 2,6-di-tert-butylphenol,2-tert-butyl-4-n-butylphenol, 2,4,6-tri-tert-butylphenol, and2,6-di-tert-butyl-4-n-butylphenol. Other commercially available hinderedphenolic antioxidants that also exhibit a thermal stability effectinclude 2,6-di-t-butyl-4-methylphenol; 2,6-di-t-butylphenol;2,2′-methylene-bis(6-t-butyl-4-methylphenol); n-octadecyl3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate;1,1,3-tris(3-t-butyl-6-methyl-4-hydroxyphenyl)butane; pentaerythrityltetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]; di-n-octadecyl(3,5-di-t-butyl-4-hydroxybenzyl)phosphonate;2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)mesitylene; andtris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate. Additional suitablethermal stabilizers include: pentaerythritol co-esters derived frompentaerythritol, (3-alkyl-4-hydroxyphenyl)-alkanoic acids andalkylthioalkanoic acids or lower alkyl esters of such acids which areuseful as stabilizers of organic material normally susceptible tooxidative and/or thermal deterioration.

Certain lubricating fluid base stocks are known in the art to exhibithigh thermal stability and as such, may be beneficial in certainembodiments of the invention. Suitable base stocks includepolyalphaolefins, dibasic acid esters, polyol esters, alkylatedaromatics, polyalkylene glycols, and phosphate esters.

A variety of polyalphaolefins may be utilized in the fuel composition ofthe invention. Polyalphaolefins are hydrocarbon polymers that contain nosulfur, phosphorus, or metals.

In another embodiment, the fuel composition may optionally include acarburetor detergent. Carburetor deposits may form in the throttle bodyand plate, idle air circuit, and in the metering orifices and jets.These deposits are a combination of contaminants from dust and engineexhaust, held together by gums formed from unsaturated hydrocarbons inthe fuel. They can alter the air/fuel ratio, cause rough idling,increased fuel consumption, and increased exhaust emissions. Carburetordetergents appropriate for use in the invention typically preventdeposits from forming and remove deposits already formed.

In yet another embodiment, the fuel composition may optionally include afuel injector detergent. Fuel injectors are very sensitive to depositsthat can reduce fuel flow and alter the injector spray pattern. Thesedeposits can make vehicles difficult to start, cause severe driveability problems, and increase fuel consumption and exhaust emissions.Suitable detergents include amine detergents and polymeric dispersants.

In another embodiment, the fuel composition may optionally include anagent to minimize combustion chamber deposits. Combustion chamberdeposits can cause an increase in the octane number requirement forvehicles as they accumulate miles. These deposits accumulate in theend-gas zone and injection port area. Suitable agents that minimizecombustion chamber deposits include polyetheramine and other proprietaryadditives are known to reduce the magnitude of combustion chamberdeposits.

The gasoline fuel compositions of various embodiments advantageously maycontain one or more drive ability additives, such as anti-knock,anti-run-on, anti-pre-ignition, and anti-misfire additives that directlyaffect the combustion process. Anti-knock additives include lead alkylsthat are no longer used in the United States. These and other metallicanti-knock additives are typically used at dosages of roughly 0.2 gmetal/liter of fuel (or about 0.1 wt % or 1000 ppm). A typical octanenumber enhancement at this dosage level is 3 units for both ResearchOctane Number (RON) and Motor Octane Number (MON). Several organiccompounds are also known to have anti-knock activity. These includearomatic amines, alcohols, and ethers that can be employed at dosages inthe 1000 ppm range. These additives work by transferring hydrogen toquench reactive radicals. Oxygenates such as methanol and MTBE alsoincrease octane number but these are used at such high dosages that theyare not really additives but blend components. Pre-ignition is generallycaused by the presence of combustion chamber deposits and is treatedusing combustion chamber detergents and by raising octane number.

The fuel composition may include a variety of demulsifiers. Demulsifiersare molecules that aid the separation of oil from water usually at verylow concentrations. They prevent formation of a water and oil mixture.Several demulsifiers are available for use in the fuel formulations ofvarious embodiments, including, for example, organic sulfonates,polyoxyalkylene glycols, oxyalkylated phenolic resins, and likematerials. Exemplary formulations include alkylaryl sulfonates,polyoxyalkylene glycols and oxyalkylated alkylphenolic resins, such asare available commercially from Baker Petrolite Corporation of SugarLand, Tex. as TOLAD®.

Several corrosion inhibitors are suitable for use in the fuelformulations of various embodiments. Suitable corrosion inhibitorsinclude dimer and trimer acids, such as are produced from tall oil fattyacids, oleic acid, linoleic acid, or the like. Other suitable corrosioninhibitors are the alkenyl succinic acid and alkenyl succinic anhydridecorrosion inhibitors such as, for example, tetrapropenylsuccinic acid,tetrapropenylsuccinic anhydride, tetradecenylsuccinic acid,tetradecenylsuccinic anhydride, hexadecenylsuccinic acid,hexadecenylsuccinic anhydride, and the like. Also useful are the halfesters of alkenyl succinic acids having 8 to 24 carbon atoms in thealkenyl group with alcohols such as the polyglycols.

If desired, the fuel compositions may contain a metal deactivator of thetype having the ability to form complexes with heavy metals such ascopper and the like. Typically, the metal deactivators used are gasolinesoluble N,N′-disalicylidene-1,2-alkanediamines orN,N′-disalicylidene-1,2-cycloalkanediamines, or mixtures thereof.Examples include N,N′-disalicylidene-1,2-ethanediamine,N,N′-disalicylidene-1,2-propanediamine,N,N′-disalicylidene-1,2-cyclo-hex-anediamine, andN,N″-disalicylidene-N′-methyl-dipropylene-triamine.

The fuel composition may include a variety of oxygenates. Oxygenates areadded to gasoline to improve octane number and to reduce emissions ofCO. These include various alcohols and ethers that are typically blendedwith gasoline to produce an oxygen content typically of up to about 2weight percent, although higher concentrations may be desirable incertain embodiments. Suitable examples of oxygenates include methanol,ethanol, methyl tertiary butyl ether (MTBE), ethyl tertiary butyl ether(ETBE), diisopropyl ether (DIPE), and tertiary amyl methyl ether (TAME).

The amount of additive that may be included in the various fuelcompositions of the invention can and will vary. The amount willtypically be the amount that is sufficient to impart the desiredfunctional property to the fuel composition.

V. Methods for Improving Oxidative Stability and Reducing Gum Formation

As demonstrated in the examples, the fuel compositions of the inventiontypically have increased oxidative stability. In addition to havingincreased oxidative stability, depending on the embodiment, the fuelcompositions may also have reduced gumming. The method of increasing theoxidative stability of a fuel composition and/or reducing gummingtypically comprises contacting a gasoline with an antioxidant mixturethat increases the oxidative stability of the fuel. In anotherembodiment, the method of increasing the oxidative stability of a fuelcomposition and/or reducing gumming typically comprises contacting agasoline and ethanol blend with an antioxidant mixture that increasesthe oxidative stability of the fuel.

Methods for determining oxidative stability of a fuel composition and/ora reduction in gum formation may be determined by methods generallyknown in the art, such as, for example, by the ASTM test D525 forOxidation Stability. Potential gum is indicative of oxidation, and maybe determined by the ASTM test D525 for Oxidation Stability as describedmore fully in the Examples. For automotive gasoline, the potential gummay be expressed as the “induction period” (sometimes called thebreakdown time). This is a measure of the time (in minutes) elapsedduring the accelerated test until the fuel absorbs oxygen rapidly. TheASTM test D525 for Oxidation Stability of Gasoline (Induction PeriodMethod) utilizes accelerated oxidation conditions to determine theoxidation stability of gasoline. This method may be utilized by askilled artisan to formulate blends of antioxidants having a suitableconcentration of each ingredient in order for the antioxidant blend toimpart the desired oxidative stability for the fuel of the invention. Inone embodiment, the fuel compositions of the present invention have aninduction time greater than 450 minutes, greater than about 500 minutes,greater than about 550 minutes, greater than about 600 minutes, greaterthan about 650 minutes, greater than about 700 minutes, greater thanabout 750 minutes, greater than about 800 minutes, greater than about850 minutes, greater than about 900 minutes, greater than about 950minutes, greater than about 1000 minutes, greater than about 1050minutes, greater than about 1100 minutes, greater than about 1150minutes, greater than about 1200 minutes, greater than about 1250minutes, greater than about 1300 minutes, greater than about 1350minutes, greater than about 1400 minutes, or greater than about 1450minutes.

Definitions

To facilitate understanding of the invention, a number of terms andabbreviations as used herein are defined below:

The term “Induction time” denotes the resistance of the fuel tooxidation.

The term “Oxidative Stability” refers to the ability to decrease therate of fuel oxidation.

The term “PPM” stands for parts per million.

As various changes could be made in the above fuel compositions,products and methods without departing from the scope of the invention,it is intended that all matter contained in the above description shallbe interpreted as illustrative and not in a limiting sense.

EXAMPLES

The following examples illustrate various iterations of fuelcompositions having improved oxidative stability.

Example 1 Improved Oxidative Stability of Fuel Compositions ComprisingEthoxyquin

The ability of the antioxidant6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, also known as ethoxyquin,to stabilize gasoline mixtures was tested. Ethoxyquin was added atconcentrations of 0.01% (100 ppm) or 0.005% (50 ppm) to gasolinecompositions comprising from 0% to 85% of ethanol. The base fuel usedfor blending was an ethanol blending Reformulated gasoline Blendstockfor Oxygen Blending (RBOB). The fuel was obtained from the terminalprior to the addition of any detergent additives or oxygenates. The fuelwas filtered through Alumina to remove any antioxidant additives thatwould be present from the refinery blendstock fuels. (See Examples 2 and3 for additional information about the base fuel used in this study.)

The oxidative stability of each of the formulations (see Table 1) wastested using the ASTM D 525 Test Method for Oxidation Stability ofGasoline (Induction Period Method). Analyses were performed according tothe listed ASTM test procedures with no modifications or deviations.Briefly, a sample of gasoline was placed in a glass sample container ina pressure vessel and oxygen was introduced to a pressure of about 100psi. The charged pressure vessel was placed in a 100° C. (212° F.) bathand the pressure was continuously monitored for 24 hours (1440 minutes).The break point of the fuel was determined when a specified drop inpressure in 15 minutes was observed. The number of minutes required toreach this point was the induction period.

Table 1 presents the induction periods, maximum and minimum pressures,and indicates whether or not a break point was observed. Ethoxyquin(ETX) increased the induction period of fuels comprising 0%, 10%, and20% ethanol about three-fold. Fuels comprising 40% or more ethanol werestable with and without the antioxidant. FIGS. 1-3 present pressureversus time plots in the absence or presence of ethoxyquin of thedifferent fuel compositions. The plots clearly indicate the breakingpoints or lack of breaking points in the various formulations. TABLE 1ASTM D 525 Test Results. Sample Induction Max Min Run Composition (%)Period Pressure Pressure # Fuel EtOH ETX (min) Break (psi) (psi) 1 100 00 238 YES 148.9 54.5 2 99.99 0 0.01 718 YES 150.5 54.4 3 89.99 10 0.01894 YES 163.7 68.3 4 90 10 0 315 YES 162.9 64.4 5 79.99 20 0.01 >1440 NoBreak 172.7 80.8 6 80 20 0 582 YES 168.0 68.3 7 59.99 40 0.01 >1440 NoBreak 168.8 114.7 8 60 40 0 >1440 No Break 166.9 66.4 9 39.99 600.01 >1440 No Break 166.1 164.4 10 40 60 0 >1440 No Break 166.0 81.8 1114.99 85 0.01 >1440 No Break 158.3 157.4 12 15 85 0 >1440 No Break 161.1150.2 13 14.995 85 0.005 >1440 No Break 158.5 157.0 14 39.995 600.005 >1440 No Break 165.0 1337 15 79.995 20 0.005 >1440 No Break 169.068.2 16 89.995 10 0.005 563 YES 170.4 69.3

Example 2 Distillation Profile of Base Fuel

The base fuel used in Example 1 was characterized by determining itsdistillation profile. This was determined using the ASTM D 86 StandardTest Method for Distillation of Petroleum Products at AtmosphericPressure. For this, a sample was placed in a round bottom flask andheated at a rate specified for samples with its vapor pressurecharacteristics. Temperatures (° F.) were recorded when the first dropwas collected (initial boiling point; IBP), at recovered volumesrepresenting 5% to 95% of the initial volume, and at the end of the test(final boiling point; FBP).

The distillation profile is presented in Table 2, as well as thepercentages of recovery, residue, and loss. TABLE 2 ASTM D 86Distillation Profile of Fuel. Measured Unit Value IBP ° F. 83.7  5% ° F.100.3 10% ° F. 114.7 15% ° F. 124.5 20% ° F. 134.2 30% ° F. 154.8 40% °F. 177.4 50% ° F. 201.5 60% ° F. 227.9 70% ° F. 258.6 80% ° F. 299.0 90%° F. 349.5 95% ° F. 383.6 FBP ° F. 421.9 Recovery % 96.5 Residue % 0.9Loss % 2.6

Example 3 Composition of Base Fuel

The base fuel used in Example 1 was characterized by determining itscomposition of hydrocarbons. This analysis was performed using the ASTMD 6729 Test Method for Determination of Individual Components in SparkIgnition Engine Fuels by Capillary High-Resolution Gas Chromatography.The method uses a 100 meter capillary column and flame ionizationdetector. A total of 385 compounds were identified. The compounds aresummarized by group in Table 3. The compounds are summarized by numberof carbons in Table 4, and composite in Table 5. TABLE 3 Base FuelComposition: Summary by Group. Group % Weight % Volume % Mole Paraffin12.957 14.844 16.232 I-Paraffins 35.824 39.009 36.675 Aromatics 29.55024.535 24.978 Mono-Aromatics 26.270 22.016 22.559 Naphthalenes 1.4001.007 1.003 Naphtheno/Olefino-Benz 1.247 1.025 0.920 Indenes 0.520 0.3940.429 Naphthenes 6.501 6.201 6.239 Mono-Naphthenes 6.046 5.776 5.894Di/Bicyclo-Naphthenes 0.051 0.046 0.032 Olefins 10.021 10.702 12.018n-Olefins 3.711 4.066 4.658 Iso-Olefins 4.528 4.877 5.410Naphtheno-Olefins 0.692 0.649 0.863 Di-Olefins 0.455 0.462 0.497Oxygenates 0.131 0.129 0.148

TABLE 4 Base Fuel Composition: Summary by Carbon. Carbon # % Weight %Volume % Mole C4 4.343 5.480 7.299 C5 14.084 16.206 19.178 C6 14.29515.409 16.349 C7 19.729 19.798 19.652 C8 17.146 16.333 15.141 C9 11.80010.611 9.369 C10 7.890 6.713 5.747 C11 3.242 2.735 2.120 C12 2.083 1.7751.238 C13 0.371 0.359 0.196

TABLE 5 Base Fuel Composition: Composite by Carbon. Group Carbon # %Weight % Volume % Mole Paraffin C4 3.601 4.549 6.039 C5 2.888 3.3723.901 C6 2.889 3.204 3.268 C7 1.729 1.849 1.682 C8 0.700 0.728 0.597 C90.348 0.355 0.265 C10 0.232 0.233 0.159 C11 0.164 0.162 0.103 C12 0.1210.118 0.069 C13 0.283 0.274 0.150 I-Paraffins C4 0.396 0.520 0.664 C56.697 7.905 9.047 C6 7.629 8.485 8.628 C7 8.657 9.319 8.421 C8 7.6347.961 6.514 C9 2.539 2.578 1.929 C10 1.177 1.173 0.806 C11 0.810 0.7920.506 C12 0.198 0.192 0.113 C13 0.088 0.085 0.047 Aromatics C12 0.1130.093 0.068 Mono-Aromatics C6 0.715 0.595 0.892 C7 4.284 3.613 4.532 C87.001 5.899 6.428 C9 7.429 6.233 6.025 C10 3.866 3.238 2.807 C11 1.5021.227 0.991 C12 1.474 1.211 0.885 Naphthalenes C10 0.662 0.478 0.500 C110.738 0.529 0.502 Naphtheno/Olefino-Benzs C10 1.247 1.025 0.920 IndenesC10 0.520 0.394 0.429 Naphthenes C8 0.054 0.050 0.047 C9 0.322 0.3020.249 C11 0.028 0.026 0.018 Mono-Naphthenes C5 0.434 0.426 0.604 C60.580 0.544 0.671 C7 2.954 2.848 2.933 C8 1.264 1.200 1.098 C9 0.5590.526 0.432 C10 0.079 0.071 0.055 C12 0.176 0.161 0.102Di/Bicyclo-Naphthenes C10 0.051 0.046 0.032 Olefins C4 0.000 0.000 0.000C6 0.046 0.049 0.053 C7 0.240 0.250 0.231 C8 0.170 0.169 0.163 C9 0.1790.181 0.142 n-Olefins C4 0.334 0.400 0.580 C5 1.650 1.860 2.293 C6 0.8810.942 1.021 C7 0.432 0.448 0.429 C8 0.182 0.185 0.158 C9 0.216 0.2140.167 C10 0.017 0.017 0.012 Iso-Olefins C5 2.015 2.246 2.800 C6 1.0481.115 1.214 C7 1.217 1.255 1.208 C9 0.208 0.221 0.161 C10 0.040 0.0400.028 Naphtheno-Olefins C5 0.180 0.171 0.258 C6 0.496 0.463 0.589 C70.016 0.015 0.016 Di-Olefins C5 0.101 0.109 0.145 C6 0.011 0.012 0.013C7 0.200 0.201 0.201 C8 0.143 0.141 0.138 Oxygenates C4 0.012 0.0110.016 C5 0.119 0.117 0.132

1. A fuel composition, the composition comprising: (a) A gasoline; (b)An ethanol; and (c) An antioxidant comprising Formula (I):

wherein: R¹, R², R³ and R⁴ are independently selected from the groupconsisting of hydrogen and an alkyl group having from 1 to about 6carbons; R⁵ is an alkoxy group having from 1 to about 12 carbons.
 2. Thefuel composition of claim 1, comprising at least one additionalantioxidant selected from the group consisting of butylatedhydroxyanisole; butylated hydroxytoluene; octyl gallate; dodecylgallate; 3,4,5-trihydroxybenzoic acid n-propyl ester;1,2,3-trihydroxybenzene; methyl linoleate; methyl oleate; methylstearate; 2,2,6,6-tetramethylpiperidinooxy;2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl;dimethyl-p-phenylaminophenoxysilane; di-p-anisylazoxides;p-hydroxydiphenylamine; ascorbyl palmitate; butylated hydroxyanisole;butylated hydroxytoluene; phenyl-alpha-naphthylamine; hydroquinone;2-tert-butylhydroquinone; 3-tertiarybutyl-4-hydroxyanisole;2,6-di-tert-butyl-4-hydroxymethylphenol;2-6-di-tert-butyl-4-methylphenol; t-tert-butyl-4-methylphenol;2-ter-butyl-4-methoxyphenol; polyphosphates; trihydroxy butyrophenone;and anoxomer.
 3. The fuel composition of claim 1, comprising at leastone additional antioxidant selected from the group consisting of2-tert-butylhydroquinone; 3,4,5-trihydroxybenzoic acid n-propyl ester;mono tertiary butyl hydroquinone; di-tert-butyl hydroquinone;1,2,3-trihydroxybenzene; 2-tert-butyl-4-hydroxyanisole;t-tert-butyl-4-methylphenol; and2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene.
 4. The fuel composition ofclaim 1, wherein the antioxidant is6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline.
 5. The fuel compositionof claim 4, wherein the fuel contains from about 20 ppm to about 1500ppm 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline.
 6. The fuelcomposition of claim 4, wherein the fuel contains from about 50 ppm toabout 500 ppm 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline.
 7. The fuelcomposition of claim 4, further comprising 2-tert-butylhydroquinone. 8.The fuel composition of claim 4, further comprising2-tert-butyl-4-hydroxyanisole; and2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene
 9. The fuel composition ofclaim 4, further comprising 2-tert-butylhydroquinone, and a paraffinoil.
 10. The fuel composition of claim 4, further comprising2-tert-butyl-4-hydroxyanisole,2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene, and a paraffin oil.
 11. Thefuel composition of claim 1, wherein the fuel comprises from about 60%to about 99% by weight gasoline and from about 1% to about 40% by weightethanol.
 12. The fuel composition of claim 1, wherein the fuel comprisesfrom about 80% to about 90% by weight gasoline and from about 10% toabout 20% by weight ethanol.
 13. The fuel composition of claim 1,wherein the fuel has substantially improved oxidative stability.
 14. Thefuel composition of claim 1, wherein the fuel has an induction time ofgreater about than 1400 minutes.
 15. The fuel composition of claim 1,wherein the fuel has substantially reduced gumming.
 16. The fuelcomposition of claim 1, further comprising an additive selected from thegroup comprising of octane improvers, drive ability additives, metaldeactivators, corrosion inhibitors, thermal stabilizers, detergents, anddemulsifiers.
 17. The fuel composition of claim 1, further comprising asolvent selected from the group consisting of a polar solvent and a nonpolar solvent.
 18. A fuel composition, the composition comprising: (a) Agasoline in an amount ranging from about 60% to about 99% by weight ofthe composition; (b) An ethanol in an amount ranging from about 1% toabout 40% by weight of the composition; and (c)6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline in an amount ranging fromabout 20 to about 1500 ppm.
 19. The fuel composition of claim 18,wherein the composition comprises about 80% to about 90% by weightgasoline; from about 10% to about 20% by weight ethanol; and from about50 ppm to about 500 ppm 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline.20. The fuel composition of claim 18, comprising at least one additionalantioxidant selected from the group consisting of butylatedhydroxyanisole; butylated hydroxytoluene; octyl gallate; dodecylgallate; 3,4,5-trihydroxybenzoic acid n-propyl ester;1,2,3-trihydroxybenzene; methyl linoleate; methyl oleate; methylstearate; 2,2,6,6-tetramethylpiperidinooxy;2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl;dimethyl-p-phenylaminophenoxysilane; di-p-anisylazoxides;p-hydroxydiphenylamine; ascorbyl palmitate; butylated hydroxyanisole;butylated hydroxytoluene; phenyl-alpha-naphthylamine; hydroquinone;2-tert-butylhydroquinone; 3-tertiarybutyl-4-hydroxyanisole;2,6-di-tert-butyl-4-hydroxymethylphenol;2-6-di-tert-butyl-4-methylphenol; t-tert-butyl-4-methylphenol;2-ter-butyl-4-methoxyphenol; polyphosphates; trihydroxy butyrophenone;and anoxomer.
 21. The fuel composition of claim 18, comprising at leastone additional antioxidant selected from the group consisting of2-tert-butylhydroquinone; 3,4,5-trihydroxybenzoic acid n-propyl ester;mono tertiary butyl hydroquinone; di-tert-butyl hydroquinone;1,2,3-trihydroxybenzene, 2-tert-butyl-4-hydroxyanisole;t-tert-butyl-4-methylphenol; and2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene.
 22. The fuel composition ofclaim 18, further comprising 2-tert-butylhydroquinone.
 23. The fuelcomposition of claim 18, further comprising2-tert-butyl-4-hydroxyanisole; and2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene
 24. The fuel composition ofclaim 18, further comprising 2-tert-butylhydroquinone, and a paraffinoil.
 25. The fuel composition of claim 18, further comprising2-tert-butyl-4-hydroxyanisole,2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene, and a paraffin oil.
 26. Thefuel composition of claim 18, wherein the fuel has an improved oxidativestability.
 27. The fuel composition of claim 18, wherein the fuel has aninduction time of greater than 1400 minutes.
 28. The fuel composition ofclaim 18, wherein the fuel has substantially reduced gumming.
 29. Thefuel composition of claim 18, wherein the ethanol is produced from asource selected from the group consisting of corn, plant-derivedcellulose material, sugarcane, sugar beet, grain sorghum, sugar cane,sugar beet, wheat, barley, potatoes, and biomass.
 30. The fuelcomposition of claim 18, further comprising an additive selected fromthe group comprising of octane improvers, drive ability additives, metaldeactivators, corrosion inhibitors, thermal stabilizers, detergents, anddemulsifiers.
 31. The fuel composition of claim 18, further a solventselected from the group consisting of a polar solvent and a non polarsolvent.
 32. A method for increasing the oxidative stability of a fuelcomposition, the fuel composition comprising gasoline and ethanol, themethod comprising contacting the fuel composition with an antioxidantcomprising Formula (I):

wherein: R¹, R², R³ and R⁴ are independently selected from the groupconsisting of hydrogen and an alkyl group having from 1 to about 6carbons; R⁵ is an alkoxy group having from 1 to about 12 carbons. 33.The method of claim 32, comprising at least one additional antioxidantselected from the group consisting of butylated hydroxyanisole;butylated hydroxytoluene; octyl gallate; dodecyl gallate;3,4,5-trihydroxybenzoic acid n-propyl ester; 1,2,3-trihydroxybenzene;methyl linoleate; methyl oleate; methyl stearate;2,2,6,6-tetramethylpiperidinooxy;2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl;dimethyl-p-phenylaminophenoxysilane; di-p-anisylazoxides;p-hydroxydiphenylamine; ascorbyl palmitate; butylated hydroxyanisole;butylated hydroxytoluene; phenyl-alpha-naphthylamine; hydroquinone;2-tert-butylhydroquinone; 3-tertiarybutyl-4-hydroxyanisole;2,6-di-tert-butyl-4-hydroxymethylphenol;2-6-di-tert-butyl-4-methylphenol; t-tert-butyl-4-methylphenol;2-ter-butyl-4-methoxyphenol; polyphosphates; trihydroxy butyrophenone;and anoxomer.
 34. The method of claim 32, comprising at least oneadditional antioxidant selected from the group consisting of2-tert-butylhydroquinone; 3,4,5-trihydroxybenzoic acid n-propyl ester;mono tertiary butyl hydroquinone; di-tert-butyl hydroquinone;1,2,3-trihydroxybenzene, 2-tert-butyl-4-hydroxyanisole,t-tert-butyl-4-methylphenol; and2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene.
 35. The method of claim 32,wherein the antioxidant is6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline.
 36. The method of claim35, wherein the fuel contains from about 20 ppm to about 1500 ppm6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline.
 37. The method of claim35, wherein the fuel contains from about 50 ppm to about 500 ppm6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline.
 38. The method of claim35, further comprising 2-tert-butylhydroquinone.
 39. The method of claim35, further comprising 2-tert-butyl-4-hydroxyanisole; and2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene
 40. The method of claim 35,further comprising 2-tert-butylhydroquinone, and a paraffin oil.
 41. Themethod of claim 35, further comprising 2-tert-butyl-4-hydroxyanisole,2,6-Di-tert-Butyl-1-Hydroxy-4-Methylbenzene, and a paraffin oil.
 42. Themethod of claim 32, wherein the fuel comprises from about 60% to about99% by weight gasoline and from about 1% to about 40% by weight ethanol.43. The method of claim 32, wherein the fuel comprises from about 80% toabout 90% by weight gasoline and from about 10% to about 20% by weightethanol.
 44. The method of claim 32, wherein the fuel has an inductiontime of greater about than 1400 minutes.
 45. The method of claim 32,wherein the ethanol is produced from a source selected from the groupconsisting of corn, plant-derived cellulose material, sugarcane, sugarbeet, grain sorghum, sugar cane, sugar beet, wheat, barley, potatoes,and biomass.